The present invention relates to a single-phase motor particularly for submersed pumps.
The motor that is normally used is a single-phase asynchronous motor which requires two stator windings in quadrature for starting.
One of the methods used in order to achieve the phase shifting of the two windings is to interpose a permanently-connected capacitor at the power supply of one of the windings.
This kind of motor is constituted by a substantially cylindrical body which contains the pack of stator windings which actuate the rotation of a rotor whose head portion protrudes at the pump coupling head.
The combined motor-pump device is used in wells which can be up to a few hundred meters deep.
If the capacitor is integrated in the motor control panel, it is necessary to carry its electrical connections to the motor, using a cable with three leads plus the ground wire.
In order to solve this problem, one possible solution is to provide the motors with an internal capacitor, providing the connections inside said motor and leading out of the motor with a cable having two leads plus the ground wire.
This solution allows to connect the motor directly to the mains power supply.
In some existing solutions, the cylindrical container of the motor is provided with a compartment for accommodating the capacitor at the lower part, i.e., opposite the pump coupling head.
Although the integration of the capacitor in the motor body allows to eliminate the electrical panel, this solution has drawbacks.
As mentioned, the capacitor is in fact arranged at the lower part of the motor, i.e., at the opposite end with respect to the pack of the stator windings and to the electrical connections which normally exit from the pump coupling head.
The power supply cables of the capacitor must therefore be appropriately insulated and pass through the entire motor, adjacent to the stator winding pack, increasing the complexity of the geometry of the motor, or it is necessary to provide an appropriate winding with the power supply connections on one side and the capacitor connections on the opposite side, but this makes it complicated, if not impossible, to produce the winding automatically.